This article aims to analyse the cultural lexical loss of Isan language as a regional language in Thailand. According to an influence of the standard Thai language toward its regional languages lead the loss of regional lexicons especially cultural lexicons. The lexicons loss in terms of linguistic perspective is used to explain the level of loss. The 5 levels of dialect loss developed by Chanthao (2016) is the framework of this research. The 70 Isan lexicons being 3 domains; appliances, instrument objects, and tradition were the data. They were collected by dictionaries and key informants. These lexicons were checked by 50 teenagers being between 20-25 years old living in Khon Kaen province, Thailand as the sampling group. The research finding was found that the 32 Isan lexicons have been used by speakers or they are being not loss or alive but there are 38 lexicons being in 5 levels of loss. Most of lexicons or 16 lexicons is in the highest level. There are 10 lexicons in the lowest level. There are 6 lexicons in high level, 3 lexicons being in medium level and 3 lexicons in low level. The lexical loss key factors of Isan language are an influence of Thai standard as only one language used in school, official as well as mass media. Having no Isan language course in primary school is one factor of lexical loss. The Isan community changed to be modern society lead to way of life change. The teenagers’ attitude toward their mother tongue, moreover, play an in crucial role to less Isan language using in the present. These issues, however, should have been studied in next research.
Lexical loss, cultural words, Isan language, Thailand, dialect, language death